Vinyl resin stabilizers



Int. Cl. cosr 45/58 US. Cl. 26045.75 15 Claims ABSTRACT OF THEDISCLOSURE Chlorine containing vinyl resins are stabilized byincorporating therein a biscyclohexanol and at least one member of thegroup consisting of tribasic lead sulfate, dibasic lead phthalate anddibasic lead phosphite.

This invention relates to a method for stabilizing chlorine-containingvinyl resins, in particular polyvinyl chloride and copolymers of vinylchloride, stabilizing compositions to be used in the method and resinsstabilized by means of said compositions.

It is known that certain antioxidant phenolic compounds stabilizeplasticized or non plasticized chlorinecontaining resins moreefiiciently if they already contain stabilizers which are acceptors ofhydrochloric acid.

Thus, stabilizing systems which comprise, firstly metallic soaps oflead, barium or cadmium, and, secondly, phenolic antioxidants have beendescribed.

In particular, the stabilizing effect of alkylidene-4,4'- bis-phenolshas been used together with the metallic soaps for the manufacture ofvinyl plastics.

We have now discovered that the use of alkylidene-4, 4-biscyclohexanolstogether with at least one member of the group consisting of tribasiclead sulfate, dibasic lead phthalate and dibasic lead phosphite givechlorine-containing vinyl plastic compositions a distinctly higherdegree of stability than do the corresponding bisphenols.

According to the present invention there is provided, a method ofstabilizing a chlorine-containing vinyl resin, which comprisesincorporating into said resin a biscyclohexanol of the formula:

HO OH wherein R and R are hydrogen or alkyl radicals containing from 1to 18 carbon atoms, R and R are hydrogen or alkyl radicals containingfrom 1 to 4 carbon atoms and m and n are integers from 1 t 4.

The invention also relates to compositions for stabilizingchlorine-containing vinyl resins, which contain such biscyclohexanols,e.g., mixtures of the stabilizers with a plasticizer, and t0chlorine-containing vinyl resins which contain such biscyclohexanols.

The following biscyclohexanols are particularly suitable for stabilizingthe vinyl resins: isopropylidene-4,4- biscyclohexanol,isobutylidene-4,4-biscyclohexanol, methylhexyldi-(4-hydroxycyclohexyl)methane, hexyl-di-(4- hydroxycyclohexyl)-methane, dimethyldi(2,6-dimethyl- 4-hydroxycyclohexyl)-methane and di-(2,6-di-tert. butyl-4-hydroxycyclohexyl -methane.

The stabilizers may be used in various ways. Thus the biscyclohexanolsmay be incorporated with a vinyl resin and the other ingredients in amixer, which may be, for example, a kneader, a heating cylinder, anextruder or a turbulent mixer. Alternatively, and more easily, thebiscyclohexanols may be dissolved in the plasticizers, if de- 3,499,868Patented Mar. 10, 1970 sired at an elevated temperature, which are addedto the resins when pliable resin blend are desired.

The biscyclohexanols according to the invention are easily prepared byhydrogenation from the corresponding bisphenols by known methods.

For example, isopropylidene-4,4-biscyclohexanol can be obtained fromisopropylidene-4,4'-bisphenol. The preparation and properties of thehigher homologues of this product have been described, for instance, byJ. C. Sheehan and G. D. Lanbach (Journal of American Chemical Society,72, 2478248l1950).

According to a preferred embodiment of the invention,isopropylidene-4,4-biscyclohexanol is used as the stabilizer; it has theadvantage of being a relatively inexpensive product, which iscommercially available for other uses in the plastic field, for instancethe manufacture of polyester resins. This product is generally calledhydrogenated bisphenol-A, which term will be hereinafter used.

It has also been found that the stabilizing activity of thebiscyclohexanols of the invention is generally more pronounced with thestabilizers which have the highest hydroxyl content. This is the case,for instance, when hydrogenated bisphenol-A is used, rather than itshigher homologues.

It is known that certain plasticizers, for example the esters ofoxo-alcohols, have an intrinsic susceptibility to ageing. Theseplasticizers deteriorate after prolonged storage and repeated handling;this becomes apparent when they are used for the manufacture of vinylcompositions.

According to one embodiment of the invention, between 20 and 20,000parts per million (p.p.m.) of the above-mentioned biscyclohexanols areincorporated with a commercial plasticizer for the resin. The advantagesof this addition will be apparent from the example given hereinafter.

It has also been found that the stabilizing effect of thebiscyclohexanols is more marked in vinyl mixtures containing basic ornormal salts of lead as metallic stabilizers.

In this respect, the method of the invention is particularlyadvantageous for the manufacture of vinyl compositions to be used forelectrical insulation, because lead salts are particularly useful asstabilizers in this case.

The following examples which are given by way of illustration only showthat the stabilizing effect of the biscyclohexanols of the invention isobtained at very low concentration of the biscyclohexanol.

EXAMPLE 1 The following ingredients were introduced into a vane mixer:

Parts Polyvinyl chloride Lucovyl DS 1300trademark) Isooctyl phthalate 46Dielectric-type kaolin 9 Lead stabilizers 6.6

The lead stabilizers comprise a mixture of 45% of tribasic leadsulphate, 45 of dibasic lead phthalate and 10% of dibasic leadphosphite.

The mixture was then gelled by passing it through a press at l25145 C.

The insulation resistance was measured on 10 metres of this cable afterimmersion of the cable for 2 'hours in water having measurementtemperatures of 20 C. or 60 C., 100 volts being applied for 2 minutes.

Ageing was carried out in a ventilated oven for 5 days at 80 C. Tomeasure the mechanical properties, a strip 9 to 10 mm. thick wasextruded at ISO- C.; the standard test pieces were cut from this strip(type H2).

(A) isooctyl phthalate containing 200 ppm. of hydrogenated bisphenol-A(B) isooctyl phthalate containing 200 ppm. of bisphenol-A, and

(C) isooctyl phthalate not containing any stabilizer.

The following results were obtained:

ELECTRICAL PROPERTIES Kilometric resistance Kilometric resistance (M9)at 20 G. (M9) at 60 C.

Ageing Vari- Ageing Vari- Before after ation, Before after ation, ageing5 days percent ageing 5 days percent A 1, G 1, 500 -6. 25 2O B 1,250 55056 22 3. 7 S2 C 1, 200 500 58. 5 19 3. 5 81. 5

MECHANICAL PROPERTIES BL (kg/cm?) E1. (percent) Ageing Vari- AgeingVari- Bet'ore after ation, Before after ation ageing 5 days percentageing 5 days percent A 256 244 4. 5 318 302 5 B 246 183 336 178 -47 C244 185 -24 304 180 40. 5

These results show the distinctly higher resistance to ageing of mixtureA containing the stabilizer according to the present invention.

EXAMPLE 2 The same composition as in Example 1 was used, except thatisooctyl phthalate was replaced weight for weight by isodecyl phthalate.The operating conditions were similar. In Formula A, the isodecylphthalate contained 200 ppm. of hydrogenated bisphenol-A; in Formula B,it contained 200 p.p.m. of bisphenol-A; in Formula C, it was used alone.The electrical and mechanical measurements, and ageing were carried outas in Example 1.

RESULTS ELECTRICAL PROPERTIES Kilometric resistance Kilometricresistance (MSZ) at 20 C. (Me) at 60 C.

Ageing Vari- Ageing Vari- Before after ation, Before after ation, ageing5 days percent ageing 5da3s percent A 1, 900 1,000 47.5 18 17.5 -0.5 B1, 400 275 -S0.5 20 4.9 -75.5 c 1,300 250 -s0.5 15.5 4.1 73.5

MECHANICAL PROPERTIES BL (kg/em!) El. (percent) Ageing Vari- AgeingVari- Bcfore after ation, Before after ation, ageing .Sdays percentageing Sdays percent A 264 260 1. 5 349 324 7 B 268 103 26.5 346 190 45C 268 201 -25 332 201 -39 EXAMPLE 3 The same composition as in Example 1was used, except that Alfol 8-10 phthalate (trademark) was used as aplasticizer. Alfols are linear commercial alcohols obtained by thepolymerization of ethylene. The operating conditions were similar. InFormula A, the Alfol 8-10 4t phthalate contained 290 ppm. ofhydrogenated bisphenol-A; in Formula B, it was used alone. Theelectrical measurements and ageing were carried out as in Example 1.

RESULTS ELE CTRICAL PROPERTIES Kilometrie resistance Kilomctricresistance (M9) at 20 G. (M9) at 60 C.

Ageing Vari- Ageing Vari- Before after ation, Before after ation, ageing5 days percent ageing 5 days percent EXAMPLE 4 The procedure employedwas similar to that of Example 3, but the Alfol 810 phthalate wastreated beforehand with activated alumina, to purify same and improveits electrical properties. The same formulae were compared, A with 200p.p.m. of hydrogenated bisphenol- A in the plasticizer and B withoutstabilization of the plasticizer Electrical measurements and ageing werecarried out as in Example 1.

RESULTS ELECTRICAL PROPERTIES Kilometrie resistance Kilometricresistance (M9) at 20 0. (M9) at 60 C.

Ageing Vari- Ageing Vari- Before after ation, Before after ation ageing5 days percent ageing 5 days percent EXAMPLE 5 The same composition wasused, except that 2-ethylhexyl phthalate was used as the plasticizer;the procedure followed was similar. In Formula A, the 2-ethylhexylphthalate contained 200 p.p.m. of hydrogenated bisphenol-A; in Formula Bit contained 200 p.p.m. of bisphenol-A; in Formula C, it was used alone.Electrical measurements and ageing were carried out as in Example 1.

RESULTS ELECTRICAL PROPERTIES Kilometrie resistance Kilometricresistance (M9) at 20 G. (M9) at 60 C.

Ageing Vari- Ageing Vari- Before after ation, Before after ation, ageing5days percent ageing 5days percent EXAMPLE 6 The following formulationwas used:

Parts CPV (Lucovyl DS 1300) 62 Z-ethylhexyl sebacate 16.5 2-ethylhexylphthalate 15.5 Lead stabilizers 3 Fillers 3.7

In the first case (A) the Z-ethylhexyl sebacate and 2-ethy1-hexylphthalate both contained 200 p.p.m. of hydrogenated bisphenol-A; in thesecond case (B), they contained 200 ppm. of bisphenol-A; in the thirdcase (C), they contained 3% of trinonylphenyl phosphite. The procedurefollowed was similar to and the electrical measurements and ageing werecarried out as in Example 1.

RESULTS ELECTRICAL PROPERTIES Kilometric resistance Kilometricresistance (M52) at 20 (M9) at 60 C.

Ageing Vari- Ageing Vari- Before after ation, Before after ation,

ageing 5 days percent ageing 5 days percent A 700 615 12 4.8 4.7 2 B 650550 15 4. 5 3. 8 15. 5 C 570 275 51. 5 4. 2 2. 5 -40. 5

EXAMPLE 7 Methylhexyldi (4 hydroxycyclohexyl)-methane was used in anamount of 200 p.p.m. in the plasticizer instead of hydrogenatedbisphenol-A, according to the conditions set forth in Example 1.Increased resistance to ageing according to the evolution of themechanical properties was observed.

EXAMPLE 8 500 p.p.m., in relation to the plasticizer, of dimethyldi-(2,6-dimethyl-4hydroxycyclohexyl)methane were used instead ofhydrogenated bisphenol-A, according to the conditions of Example 1, witha similar increase in the resistance to ageing.

What we claim is:

1. A stabilized resinous composition comprising (a) achlorine-containing vinyl resin, (b) a biscyclohexanol of the formula:

wherein R and R are hydrogen or alkyl radicals containing from 1 to 18atoms, R and R are hydrogen or alkyl radicals containing from 1 to 4carbon atoms and m and n are integers from 1 to 4 and (c) at least onesubstance selected from the group consisting of tribasic lead sulfate,dibasic lead phthalate and dibasic lead phosphite.

2. A composition according to claim 1 in which the biscyclohexanol isisopropylidene-4,4'biscyclohexanol.

3. A composition according to claim 1 in which the biscyclohexanol isisobutylidene-4,4'-biscyclohexanol.

4. A composition according to claim 1 in which the biscyclohexanol ismethylhexyldi-(4-hydroxycyclohexyl)- methane.

5. A composition according to claim 1 in which the biscyclohexanol ishexyldi (4 hydroxycyclohexyl)- methane.

6. A composition according to claim 1 in which the biscyclohexanol isdimethyldi (2,6-dimethyl-4-hydroxycyclohexyD-methane.

7. A composition according to claim 1 in which the biscyclohexanol is di(2,6-di-tert.-butyl-4-hydr0xycycloheXyl)-methane.

8. A composition according to claim 1 in which the amount of thebiscyclohexanol in the composition is from 20 to 20,000 parts permillion based on the weight of the chlorine-containing vinyl resin.

9. A stabilizing composition for a chlorine-containing vinyl resin whichcomprises a biscyclohexanol of the formula:

wherein R and R are hydrogen or alkyl radicals containing from 1 to 18carbon atoms, R and R are hydrogen or alkyl radicals containing from 1to 4 carbon atoms and m and n are integers from 1 to 4 and at least onesubstance selected from the group consisting of tribasic lead sulfate,dibasic lead phthalate and dibasic lead phosphite.

10. A composition according to claim 9 in which the biscyclohexanol isisopropylidene-4,4'biscyclohexanol.

11. A composition according to claim 9 in which the biscyclohexanol isisobutylidene-4,4'biscyclohexanol.

12. A composition according to claim 9 in which the biscyclohexanol ismethylhexyldi-(4-hydroXycycloheXyl) methane.

13. A composition according to claim 9 in which the biscyclohexanol ishexyldi (4 hydroxycyclohexybmethane.

14. A composition according to claim 9 in which the biscyclohexanol isdimethyldi-(2,6-dimethyl-4-hydroxycycloheXyl)-methane.

15. A composition according to claim 9 in which the biscyclohexanol isdi-(2,6-di-tert.-butyl-4-hydroxycycloheXyl)-methane.

References Cited UNITED STATES PATENTS 1/1953 Fischer et a1. 260-4595OTHER REFERENCES DONALD E. CZAJA, Primary Examiner V. P. HOKE, AssistantExaminer US. Cl. X.R.

